BALTIMORE — A species of octopus known for being solitary and asocial shows greater interest in others after being exposed to MDMA, the party drug better known as ecstasy, a study reveals.
When humans take MDMA, our brains are flooded with high levels of serotonin, dopamine, and oxytocin, producing feelings of euphoria and emotional closeness, making individuals more prone to wanting to connect with one another. Researchers with several different universities across the U.S. found that the loner two-spot octopus responds to ecstasy in a similar way to humans.
“Despite anatomical differences between octopus and human brain, we’ve shown that there are molecular similarities in the serotonin transporter gene,” explains Gul Dolen of Johns Hopkins University in media release, noting that this gene encodes a transmembrane protein that becomes the primary binding site for MDMA. “These molecular similarities are sufficient to enable MDMA to induce prosocial behaviors in octopuses.”
The research team studied the two-spot octopus because they can be bred and their behavior studied in a lab. The species is also the only octopus whose genome is fully sequenced, allowing the researchers to compare their genes with human genes.
Even though the history of humans and octopuses are separated by more than 500 million years, the researchers’ genomic analysis revealed that the two-spot octopus has the same serotonin transporter gene that humans have, which is a binding site of MDMA.
The authors tested the octopuses’ interest in each other while sober and under the influence of MDMA. They found that the sea creatures were more interested in each other — and especially in other females — while sober, than the researchers originally thought. While under the influence of MDMA, the authors were surprised to see an even greater level of interaction, including between males. They also displayed an unusual level of physical contact with one another that the authors believed to be exploratory, rather than aggressive.
Researchers are now working to sequence the genomes of two other species of octopus that also display distinct, but different types of social behavior. They hope their work will shed more insight into the evolution of social behavior.
The study was published in the journal Current Biology.